In recent years, as a communication interface for transmitting image and audio data from a source device to a sink device at high speed, for example, interfaces such as HDMI (High Definition Multimedia Interface) and so forth have come into widespread use. Examples of the source device include game machines, DVD (Digital Versatile Disc) recorders, set top boxes, and other AV sources (Audio Visual sources). Examples of the sink device include television receivers, projectors, and other displays. For example, in NPL 1, the details of the HDMI standard are described.